Buggy code:
public class FeatureCallValidator extends AbstractDeclarativeValidator { @ Inject protected UIStrings uiStrings ; @ Inject private IdentifiableSimpleNameProvider nameProvider ; @ Check public void checkInvalidFeatureLinked ( XAbstractFeatureCall featureCall ) { } @ Check public void checkInvalidFeatureLinked ( XConstructorCall constructorCall ) { } protected void error ( XAbstractFeatureCall featureCall , String issueCode ) { String message = null ; if ( FEATURE_NOT_VISIBLE . equals ( issueCode ) ) message = ( "Feature<seq2seq4repair_space>" + ( nameProvider . getSimpleName ( featureCall . getFeature ( ) ) ) ) + "<seq2seq4repair_space>is<seq2seq4repair_space>not<seq2seq4repair_space>visible" ; else if ( INVALID_NUMBER_OF_ARGUMENTS . equals ( issueCode ) ) { message = "Invalid<seq2seq4repair_space>number<seq2seq4repair_space>of<seq2seq4repair_space>arguments.<seq2seq4repair_space>Expected<seq2seq4repair_space>" + ( uiStrings . parameters ( featureCall . getFeature ( ) ) ) ; } else if ( INVALID_NUMBER_OF_TYPE_ARGUMENTS . equals ( issueCode ) ) { message = ( ( "Invalid<seq2seq4repair_space>number<seq2seq4repair_space>of<seq2seq4repair_space>type<seq2seq4repair_space>arguments.<seq2seq4repair_space>Expected<seq2seq4repair_space>" + ( uiStrings . typeParameters ( featureCall . getFeature ( ) ) ) ) + "<seq2seq4repair_space>but<seq2seq4repair_space>got<seq2seq4repair_space>" ) + ( uiStrings . typeArguments ( featureCall ) ) ; } else if ( ( INVALID_ARGUMENT_TYPES . equals ( issueCode ) ) || ( INVALID_GENERIC_ARGUMENT_TYPES . equals ( issueCode ) ) ) { } else if ( ASSIGNMENT_TARGET_IS_NOT_WRITEABLE . equals ( issueCode ) ) { message = ( "Feature<seq2seq4repair_space>" + ( nameProvider . getSimpleName ( featureCall . getFeature ( ) ) ) ) + "<seq2seq4repair_space>is<seq2seq4repair_space>not<seq2seq4repair_space>writeable." ; } else if ( INSTANCE_ACCESS_TO_STATIC_MEMBER . equals ( issueCode ) ) { message = "Instance<seq2seq4repair_space>access<seq2seq4repair_space>to<seq2seq4repair_space>static<seq2seq4repair_space>member<seq2seq4repair_space>" + ( nameProvider . getSimpleName ( featureCall . getFeature ( ) ) ) ; } else if ( STATIC_ACCESS_TO_INSTANCE_MEMBER . equals ( issueCode ) ) { message = "Static<seq2seq4repair_space>access<seq2seq4repair_space>to<seq2seq4repair_space>instance<seq2seq4repair_space>member<seq2seq4repair_space>" + ( nameProvider . getSimpleName ( featureCall . getFeature ( ) ) ) ; } else if ( FIELD_ACCESS_WITH_PARENTHESES . equals ( issueCode ) ) { message = ( "Cannot<seq2seq4repair_space>access<seq2seq4repair_space>field<seq2seq4repair_space>" + ( nameProvider . getSimpleName ( featureCall . getFeature ( ) ) ) ) + "<seq2seq4repair_space>with<seq2seq4repair_space>parentheses" ; } else if ( LOCAL_VAR_ACCESS_WITH_PARENTHESES . equals ( issueCode ) ) { message = ( "Cannot<seq2seq4repair_space>access<seq2seq4repair_space>local<seq2seq4repair_space>variable<seq2seq4repair_space>" + ( nameProvider . getSimpleName ( featureCall . getFeature ( ) ) ) ) + "<seq2seq4repair_space>with<seq2seq4repair_space>parentheses" ; } else if ( METHOD_ACCESS_WITHOUT_PARENTHESES . equals ( issueCode ) ) { message = "Missing<seq2seq4repair_space>parentheses<seq2seq4repair_space>for<seq2seq4repair_space>calling<seq2seq4repair_space>method<seq2seq4repair_space>" + ( featureCall . getFeature ( ) . getIdentifier ( ) ) ; } else if ( INVALID_MUTABLE_VARIABLE_ACCESS . equals ( issueCode ) ) { message = ( "Cannot<seq2seq4repair_space>refer<seq2seq4repair_space>to<seq2seq4repair_space>a<seq2seq4repair_space>non-final<seq2seq4repair_space>variable<seq2seq4repair_space>" + ( featureCall . getFeature ( ) . getIdentifier ( ) ) ) + "<seq2seq4repair_space>from<seq2seq4repair_space>within<seq2seq4repair_space>a<seq2seq4repair_space>closure" ; } else { <START_BUG> message = "Missig<seq2seq4repair_space>error<seq2seq4repair_space>message<seq2seq4repair_space>for<seq2seq4repair_space>" + issueCode ; <END_BUG> } if ( message != null ) error ( message , null , INSIGNIFICANT_INDEX , issueCode ) ; } protected void error ( XConstructorCall constructorCall , String issueCode ) { } @ Override public void register ( EValidatorRegistrar registrar ) { } }

Fix:
message = "Missing<seq2seq4repair_space>error<seq2seq4repair_space>message<seq2seq4repair_space>for<seq2seq4repair_space>" + issueCode ;